<?php
//echo strlen("Hello World! What a nice day!");
//echo strpos("Hello World! What a nice day!","day");
//echo str_word_count("Hello World! What a nice day! Hello World!");
//echo strrev("Hello World! What a nice day");
//echo str_replace("day","world","Hello World! What a nice day");
//$arr = ["Hello","world","what","nice","day"];
//echo implode("+",$arr);
//echo join("-",$arr);
//echo trim(" Hello world ");
//echo md5("123456 Hello World! What a nice day!Hello World! What a nice day!Hello World! What a nice day!");
//echo crypt("123456 Hello World! What a nice day!Hello World! What a nice day!Hello World! What a nice day!");
//echo strtolower("Hello WoRld");
//echo strtoupper("Hello WoRld");
//echo substr_count("Hello World! What a nice World!","World");




$arr=["a","b","c",3.4,2,"D",8];
for($i=0; $i<count($arr); $i++){
    if(is_numeric($arr[$i])){
        echo $arr[$i]*2;
    }else if (is_string($arr[$i])){
        echo $arr[$i].="a";
    };
    echo "<br>";
}
